As exemplified in Becker U.S. Pat. No. 3,159,251, it has been known to make a flexible corner from a metal strip having two mutually perpendicular flanges, one of which has spaced notches along its length, and a stretchable tape covering an outer side of the notched flange. As explained therein, the flexible corner is useful for trimming a curved wall of a building column passing through a generally circular cutout in a suspended ceiling system, which comprises ceiling tiles supported by a suspended grid. A substantially similar corner having similar utility and employing a metal strip and a stretchable tape is disclosed in Becker U.S. Pat. No. 5,247,769.
Having similar utility, a flexible corner made from a hard but flexible, polyvinyl chloride strip having two mutually perpendicular flanges, one of which has spaced notches along its length, and a stretchable tape covering an outer side of the notched flange has been available commercially for several years from Trim-Tex, Inc. of Lincolnwood, Ill., under Stock No. 8158.
When such a flexible corner is used with a cylindrical column passing through a circular opening in a suspended ceiling system, the other flange is curved around the cylindrical column so as to spread the notches in the notched flange, and so as to stretch the tape. As supported by a suspended grid comprising grid members, adjacent ceiling tiles are provided with cut edges defining a substantially circular cutout, through which the cylindrical column passes. In a given installation, the notched flange may have to support some of the weight of the suspended ceiling system, particularly if and where cut ends of adjacent grid members overlie the notched flange.
Although the flexible corner noted above as available commercially from Trim-Tex, Inc., has proved to be generally acceptable to contractors and other users, it has not been entirely satisfactory. While the stretched tape is intended to conceal the spread notches, the cut edges of adjacent ceiling tiles, and the cut ends of adjacent grid members and to present a smooth appearance along its lower surface, it is difficult to avoid forming noticeable reliefs in the stretched tape, in a pattern corresponding generally to the spread notches.
Recently, it has been proposed by another party to employ an elongate angle, which is extruded from a soft, pliable, polymeric material so as to have two mutually perpendicular flanges, neither of which has any notches. If one flange is curved around a cylindrical column, the other flange is stretched into an annular shape, which is intended to present a smooth appearance along its lower surface. If one flange is curved oppositely, the other flange assumes a generally annular but somewhat rippled shape, which can be substantially smoothed by heating of its lower surface by means of a heat gun.
The elongate angle described in the preceding paragraph may not be entirely satisfactory when used with a cylindrical column and with a suspended ceiling system, as the pliable material of the stretched flange tends to sag noticeably, particularly if and where the stretched flange has to bear some of the weight of the suspended ceiling system.